This study tested the hypothesis that whole-body protein kinetics remain low in children with edematous malnutrition and acute infection. Thirteen children with edematous malnutrition and acute infection (subjects) were compared with 14 uninfected children with edematous malnutrition early in recovery (control children). Protein kinetics were determined by using a primed, constant intravenous infusion of [13C] leucine and [15N2]urea in the post-absorptive state. Calculations of rates of whole-body protein synthesis and breakdown were based on the rate of leucine appearance; the rate of leucine oxidation was estimated from the rate of urea appearance. The absence of the expected increase in the rate of protein turnover during acute infection in edematous malnutrition implies that acute phase proteins are made with a corresponding depletion of muscle, hepatic, and other body proteins such as albumin, and that there may also be a blunting of the acute phase response.